SRS is a free, open-source real-time video server supporting RTMP, WebRTC, HLS, and SRT. Learn features, use cases, and how it compares.
SRS, short for Simple Realtime Server, is an open-source real-time video streaming server that began development in 2013. It is designed to be a lightweight but high-efficiency media server capable of ingesting live video from encoders like OBS Studio or FFmpeg and redistributing it across a wide range of streaming protocols.
The project is maintained as a community-driven open-source effort under the ossrs GitHub organization and published at ossrs.io. SRS is written in ANSI C++ and uses coroutine-based concurrency, which its maintainers describe as avoiding the complexity of traditional async callback-based streaming server designs, while remaining portable across Linux, Windows, and macOS.
SRS supports an unusually broad set of streaming protocols out of the box, including RTMP, WebRTC, HLS, HTTP-FLV, HTTP-TS, SRT, MPEG-DASH, and GB28181, along with codec support for H.264, H.265, AV1, VP9, AAC, Opus, and G.711. This lets SRS act as a protocol gateway, converting a single incoming stream, for example RTMP from OBS, into multiple output formats simultaneously, such as WebRTC for low-latency browser playback and HLS for broad compatibility. SRS is also built to be cloud-native, with an official Docker image, Kubernetes deployment support, and built-in telemetry for monitoring streaming infrastructure at scale.
SRS is completely free and open source under the MIT license, with no paid tiers, subscriptions, or per-stream fees from the project itself. Organizations deploy SRS on their own servers or cloud infrastructure and pay only for their own hosting and bandwidth costs. Support is community-based through GitHub issues, the project blog, and documentation rather than a commercial support contract.
Yes, SRS is completely free and open source under the MIT license.
SRS stands for Simple Realtime Server.
SRS supports RTMP, WebRTC, HLS, HTTP-FLV, HTTP-TS, SRT, MPEG-DASH, and GB28181.
The SRS project began in 2013.
Yes, SRS provides an official Docker image and supports Kubernetes deployment.
SRS is used to build live streaming platforms, video conferencing backends, and protocol-conversion gateways between RTMP, SRT, and WebRTC.
SRS is written in ANSI C++ (98).
Yes, SRS can output WebRTC and SRT for low-latency delivery in addition to higher-latency formats like HLS.